Downhole Tool System and Method

ABSTRACT

The present invention comprises a novel thread form and slip alignment device and method for anchoring drillable downhole tools, such as fracturing plugs, bridge plugs, or cement retainers within a wellbore. The slips are oriented circumferentially about upper and lower cones between upper and lower slips and upper and lower load members whereby the downhole tool is capable of withstanding piston forces resulting from differential pressure from above and below the set position through the utilization of a sealing element to maintain differential pressure from above and/or below the tool. Upon wellbore pressure application above and/or below the plug, relative axial movement between the mandrel and the slips, tool, and cones occurs until halted by an upper and lower stop disposed on the mandrel at each distal and proximate end. Further, components used in the slip alignment feature may be manufactured from weak materials or anisotropic material properties for milling.

STATEMENT OF PRIORITY

The present application claims priority to U.S. Provisional Application No. 62/586,091, titled “High Shear Strength Mating Helical Thread Form for Downhole Tool,” filed Nov. 14, 2017, and also claims priority to U.S. Provisional Application No. 62/586,100, titled “Slip Alignment Feature Downhole Tool,” also filed Nov. 14, 2017.

FIELD OF THE INVENTION

The field of the invention relates generally to borehole barriers used in oil and gas wellbores that perceive pressure from above and/or below and utilize materials that are easily milled for removal after use. More particularly, the present invention relates to an apparatus and methods of use for utilizing a drillable frac plug, bridge plug, cement retainer, or other downhole apparatus for use in a variety of well stimulation techniques designed to increase formation permeability and porosity in attempts to induce greater well production. Additionally, the present invention relates to methods and apparatus for a drillable frac plug, bridge plug, cement retainer, or other downhole apparatus, which may utilize threaded connections for mating components and assemblies.

BACKGROUND OF THE INVENTION

Hydrocarbon recovery methods have experienced steady advancement of evolving completion techniques since the industrial revolution as a result for the world's increasing demand for and reliance upon hydrocarbons and their biproducts. Coupled with the depletion of naturally producing, formation pressure driven wells and reduced numbers of formations with high permeability and porosity, the landscape for conventional completion methods has gradually transformed into the economically driven unconventional completion market. Where early wellbores could be drilled and produced with little use of secondary or tertiary completion methods, the lower permeable and/or low porosity formations (e.g. shale) of the modern era require multiple hydraulic fracturing stimulations, treatments, and re-stimulations in order to recover hydrocarbons from the near wellbore formation rock.

In order to maximize recovery performance, completion flexibility, and to minimize completion costs, unconventional wellbore completions increasingly utilize hydraulic fracturing as well as a variety of multistage completion methods to induce the recovery of natural gas and petroleum through pressurized well stimulation. Hydraulic fracturing operations are performed by introducing high pressure fluid, gas, and/or foams (i.e. fracturing medium) into the wellbore at high rates until fractures propagate into the formation as a means of creating artificial permeability and porosity channels. The fracturing medium (e.g. fluid, gas or foam) is further used during each well completion to sand or proppant into the fissures created during fracturing in order to maintain fracture connectivity and hold or “prop” the fractures open after applied pressure is removed. However, the formation volume that is stimulated by the hydraulic fracturing operation is limited by the formation properties and fracturing mechanics of the reservoir, which requires the hydraulic fracturing operation to be repeated at predetermined intervals throughout the wellbore (e.g. multistage completions) for the formation to be economically viable.

A hydraulic fracturing completion begins after the well has been drilled, a casing with a toe sleeve has been installed and cemented, and all wellbore construction operations have been completed. The toe sleeve will then be opened through the application of hydraulic pressure within the wellbore or through mechanical activation via a coil tubing or jointed pipe conveyed shifting tool, to create ports through the casing to establish connectivity between the wellbore and the near wellbore formation rock. Once the toe sleeve ports are open, wellbore fluid will be able to be pumped from the wellbore and into the formation rock, allowing for pump down operations for a variety of downhole tools. Perforating guns may be deployed by pumping down a wireline assembly and used to perforate the casing in desired locations, increasing the wellbore connectivity beyond the toe sleeve ports. Following the removal of any equipment in the wellbore, hydraulic fracturing stimulations will commence with the application of high rate and high pressure fracturing medium from the surface, until the desired completion parameters have been met for that stage (e.g. the first stage).

A fracturing plugs or bridge plug is one example of a downhole tool that may be used for zonal isolation to separate targeted stages from previously completed (e.g. hydraulically fractured) stages during multistage completion operations. A wireline bottom hole assembly (e.g. BHA) containing locating equipment, perforating guns, a setting tool, a setting tool adapter kit, and a fracturing or bridge plug can be pumped downhole to a predetermined target depth whereby an electronic signal is sent from surface to the downhole tool to activate the setting tool and set and release the fracturing or bridge plug. Alternatively, a hydraulic setting tool may be used in a BHA (Bottom Hole Assembly) and the BHA may be deployed to the target depth via jointed pipe or coil tubing, set and then released from the plug with application of hydraulic pressure. The BHA is then moved uphole and additional electronic signals are sent from the surface to activate the perforating gun assemblies to perforate the casing in desired locations thus creating wellbore connectivity above the set plug. In the case of a fracturing plug, a through inner diameter bore exist and a ball is required to be from surface or run in place with the BHA in order to plug the bore of the fracturing plug to establish a pressure differential and/or fluid diversion. Once all BHA equipment has been removed from the wellbore and a ball has been dropped and seated on the set plug (in the case of a ball drop style fracturing plug), hydraulic fracturing operations will take place until all completion parameters have been met for the current stage. This process (e.g. BHA pump down, plug setting event, perforating, pull out of hole, and hydraulic fracturing) will generally be repeated until all planned stages (which may exceed 75 stages) of the well are completed.

One potential shortcoming in the use of fracturing plugs or bridge plugs for multistage completions becomes apparent after all plugs have been installed and each stage has been fracked. Manifestly, once the formation has been stimulated, and permeability and connectivity of the formation rock has been increased to enable economically viable production of the reservoir hydrocarbons, the wellbore is now obstructed with the plugs used to isolate each stage in order to optimize the fracturing operations. The plugs must be removed from the wellbore in order for full production to begin, which either requires the mobilization and use of coil tubing or jointed pipe surface assets for downhole plug mill out operations, or, in the case of dissolvable fracturing plugs, requires a halt in operations until the installed plugs dissolve completely. Additionally, plug removal options have significant financial impacts, such as in the cost associated in maintaining surface assets on site during mill out operations, as well as the cost of nonproductive time during waiting for plugs to completely dissolve. With respect to the fracturing or bridge plug unit, the primary cause for increased mill out time or increased dissolve time, and therefore increased asset utilization time or increased nonproductive dissolve time, is the overall volume of the plug. For instance, if plug A is 70% the volume of a plug B, the amount of material that is required to be milled or dissolved for plug A is 70% of that required for plug B, translating to reduced plug removal times.

A general architectural makeup of typical hydraulic fracturing plugs, bridge plugs, or cement retainers, consist of a mandrel with or without a through inner diameter bore, where outer components disposed concentrically about the mandrel. The outer components may contain any number of load rings, slips, cones, packing elements, end stops, pins, and shearing devices. The mandrel generally contains a ball seat, in the case of a fracturing plug, or an installed inner diameter plug that is positioned above the packing element for safe mill out operations, in the case of a bridge plug. The mandrel generally contains connection areas for bonding or pinning of outer components, or threaded interfaces for fastening components that have variable linear engagement, such as end stop components. A typically elastomeric packing element is used to engage and seal against the casing tubular inner diameter after application of setting load from the setting tool, and is generally disposed concentrically about the mandrel outer diameter between a set of upper and lower slips and cones. The slips may generally be a complete ring that breaks into individual petals or pads, or individual segments held together by wires, pins, bands, etc., having an angular or conical inner diameter surface for use in moving along the ramp of the upper and/or lower cone angle and generally having a hardened or high friction feature disposed on or within the outer diameter surface for use in broaching and/or forming a friction lock as a means of anchoring the slip, and thus the cone, relative to the position within the casing tubular. Additionally, a load ring is generally used to ensure that even load is applied to the upper slip during the setting event and is positioned between the upper slip and an upper stop component. The upper stop component may be an integral feature within the mandrel itself, a sleeve bonded and/or pinned to the mandrel, or a separate component fastened to the mandrel via a threaded connection. The lower stop follows the same conditions as the upper stop but is disposed on the lower end of the mandrel. The plug assembly may contain variations of pinned or bonded components either for increased strength or designed failure points. Also, plugs generally utilize shear off mechanisms such as shear features (e.g. shear screws, shear rings, shear pins, shear studs, etc.) or release features (e.g. collets, latches, threads, etc.) to ensure that a full setting force is imparted into the plug prior to release from the plug.

A setting tool adapter kit is used to fasten the plug to the setting tool and to hold the plug axially and concentrically in place with the setting tool during the setting event. Generally, an adapter kit consists of a mandrel, a setting sleeve, and any combination of adjustment components and debris or entry guide components. A mandrel may serve as a bridge between the plug mandrel (or any fixed component of the plug that does not translate during the setting event) and the fixed end of the setting tool. The setting sleeve is attached to the moveable component of the setting tool, is free floating concentrically about the remaining adapter kit and plug components and is used to impart setting force generated by the setting tool into the plug during the setting event. Depending on the complexity of the adapter kit, the general architecture of the setting tool adapter kit includes adjustment components for modifying axially varying component placement, entry guide or debris barrier components, and/or anti-pre-stroke features.

During the setting event, the setting tool strokes axially relative to the adapter kit mandrel and plug mandrel (and any fixed component of the plug that does not translate during the setting event) resulting in axially movement of the setting sleeve which imparts a setting load into the outer components of the plug. A general setting sequence follows with axial displacement and load application on the load ring, upper slip, upper cone, packing element, lower cone. Upon application of setting force from the setting tool, the slips will move axially relative to its adjacent cone (either above or below the packing element) and will expand radial outward as the slip moves along the angled face of the cone until contact with and surface penetration of the casing occurs. Each set slip produces an anchor point against axial movement for the slip and for the adjacent cone and, in a component system with an upper and lower set of slip and cone between a packing element, the setting of the upper and lower set of slip and cone ensures that no movement can occur after setting load is transmitted through the packing element and both sets of slips and cones, thus ensuring that packing element pack off is securely maintained. Additionally, load transmitted into both slip and cone interfaces is also transferred into the packing element resulting in the axial reduction in length of the packing element when pressed between upper and lower slips and cones. As a result, radial expansion of the packing element occurs due to conservation of the component volume until contact with the casing is established. The load path transfers through the end stop and into the mandrel through the end stop to mandrel interface (either a bonded, pines, and/or threaded connection) and in doing so alters from a compressive load for the outer components and a shear load through the end stop mandrel interface to a tensile load through the mandrel and a shear load through the shear off mechanism. When the applied setting force from the setting tool reaches the shear load threshold for the shear off mechanism (or another type of disengagement method such as a release feature), the setting tool and setting tool adapter kit releases from the plug, leaving the plug in the set position, wherein the BHA can begin the pull out of hole operation.

When the plug is in the “set” position, the load ring, upper slip, upper cone, packing element, lower cone, and lower slip have been axially displaced downhole along the mandrel and the lower slip is shouldered against the lower end stop. Because the upper and lower slip only anchor the components between them (e.g. upper cone, packing element, lower cone), the mandrel and all other plug components are free to translate relative to the anchored components in the uphole and/or downhole directions. This movement of the non-anchored components is produced due to pressure differential and resulting piston affects imparted on the plug components, which can be caused by pressure drop from flowing through the plug from the uphole and/or downhole direction, landing a ball in the plug mandrel and applying differential pressure from uphole of the set plug, and/or, in the case a bridge plug, applying differential pressure from uphole and/or downhole of the set plug. When the mandrel and all other free-to-move components disposed on the plug mandrels translate relative to the anchored components (e.g. slips, cones, and packing element) the translation ends when the upper or lower end stop makes contact with the anchored component (or a load ring intermediately between the end stops and anchored components), at which point the respective end stop and mandrel interface is loaded in shear as a result of the piston affect due to applied pressure.

A disadvantage of this application stems from the general weakness of the materials used for fracturing plugs, bridge plugs, and/or cement retainers. Material selection for these products is driven by their ease of milling, and generally include composites (e.g. filament wound, convolute wrap, laminate composite sheets, molded plastic/phenolics/resins, etc.), low density metals, ceramics, sintered metals, and/or magnesium based alloys. Although these materials provide ease of milling, they have reduced physical material properties, in the case of the crystalline structure metallic material options, or in the case of composite materials, they are entirely anisotropic materials. This means that the material properties of composite materials are independent of the direction of applied force. For example, where one component may be strong in a hoop load application, it would sacrifice performance and be weak in a tensile application. Additionally, non-molded composite components are often engineered products, in that they are designed for specific load cases, and wind angles, fiber tension, resin content, etc. are controlled to manufacture a component for a specific load and/or for several separate load cases throughout the component. However, because composite material properties are anisotropic, composite components are not suited to withstand combined loading, and/or to withstand separate and different load cases although applied independently. Furthermore, composite components for downhole tools are often tubular in shape, due to the nature of the wellbore application, and although the fiber or fabric reinforcement used to construct these components are inherently strong when in tension, and the layup design for each part utilizes this property in manufacturing design, the interlaminar layers between planes of fibers or fabric (e.g. layers that are reinforced primarily by resin instead of fibers or fabric) are inherently weak. As a result, composite components are generally inherently weak when subjected to combined and asymmetric loading that act upon interlaminar planes. For example, slip petals supported by a cone impart a shear and hoop load onto the supporting cone, and when not oriented uniformly about the cone axis, the loading is asymmetric and results in high stress concentrations and often failure of one or both components. For this reason, parts that are exposed to combined and asymmetric loads must be reinforced by ancillary components (e.g. reinforcement pins have increased component lengths to compensate for weak shear strength (by increasing the equivalent shear area), utilize complex multi-material manufacturing, or use complex wind pattern designs that are almost impossible to evaluate in quality control processes without utilizing destructive methods. Additionally, composite components are generally inherently weak when subjected to combined and asymmetric loading that act upon interlaminar planes. For example, slip petals supported by a cone impart a shear and hoop load onto the supporting cone, and when not oriented uniformly about the cone axis, where loading is asymmetric and results in high stress concentrations and often failure of one or both components. For this reason, parts that are exposed to combined and asymmetric loads must be reinforced by ancillary components (e.g. reinforcement pins), have increased component lengths to compensate for weak shear strength (by increasing the equivalent shear area), utilize complex multi-material manufacturing, and/or use complex wind pattern designs that are almost impossible to evaluate in quality control processes without utilizing destructive methods.

Therefore, a need exists in the field for a novel thread form used to fasten components with variable lengths of engagements that can withstand high shear loads, for use with components of low shear strength or anisotropic material properties, such as those used by fracturing plugs, by transferring load applied to the threaded interface radially inward and outward into the mating components, rather than along the thread form root shear diameter. A further need exists in the field for a novel alignment feature used to rotationally orient a slip relative to a cone, for use with components of low strength or anisotropic material properties, such as those used by fracturing plugs, in order to uniformly distribute load applied to the supporting interface, rather than create asymmetrically located stress concentrations.

SUMMARY OF THE INVENTION

The present invention comprises a novel slip alignment feature such that a slip used to anchor a downhole apparatus in place within a wellbore is disposed between a cone and a guide member wherein the cone and slip are adjacent along tapered faces and the slip and load member shoulder adjacently against either a tapered or perpendicular face and, furthermore, the interface between the slip and guide member shoulder is shared by a plurality of aligning features extending radially outward to control orientation of the slip relative to the load member throughout all functions of the downhole apparatus and thus control orientation of the slip relative to the cone throughout the same functions of the downhole apparatus. Orientation resulting from slip and guide member alignment is such that, when the slips ride up the cone and anchor against the wellbore wall, the resulting uniform placement of the split petals impart a circumferentially symmetric load distribution into the supporting cone. The alignment feature disposed between the slip and guide member interface may be features of each constituent component in the form of grooved and or guiding geometry, may be added components used to follow guide geometry, and/or a combination thereof. In preferred embodiments, one or more of the components used in the slip alignment feature are manufactured from materials with weak material or anisotropic material properties, such as, but not limited to composite, magnesium alloys, and molded plastics, such as for use in fracturing plugs, bridge plugs, and/or cement retainers.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the present invention are illustrated as an example and are not limited by the figures of the accompanying drawings, in which like reference may indicate similar elements and in which:

FIG. 1 depicts an exterior view of one example of a high shear strength male thread form according to various embodiments of the present invention.

FIG. 2 illustrates a cross section view of one example of a high shear strength male thread form positioned on a mandrel exterior diameter according to various embodiments described herein.

FIG. 3 shows a cross section view of one example of a high shear strength female thread form positioned on a sleeve interior diameter according to various embodiments described herein.

FIG. 4 shows a cross section view of the mandrel positioned concentrically within the sleeve and the thread profiles aligned as they would be when assembled according to various embodiments described herein.

FIG. 5A shows cross section view from FIG. 4 with hatching depicting the fiber layers formed by composite winding processes oriented circumferentially about each component axis. FIG. 5B shows cross section view from FIG. 4 with hatching depicting the fiber layers formed by composite winding processes oriented conically about each component axis. FIG. 5C shows cross section view from FIG. 4 with hatching depicting the sheet layers formed by composite laminate processes oriented perpendicularly about each component axis.

FIG. 6 depicts an embodiment of a downhole tool, such as a plug assembly 33, of one embodiment of the present invention.

FIG. 7 shows an embodiment of a downhole tool, such as a plug assembly 33, with wireline adapter kit and setting tool, being run in hole.

FIG. 8 shows an embodiment of a downhole tool, such as a plug assembly 33, in the set position having a pressure (P) supplied from above, without a pump down ring 83.

FIG. 9 shows an isometric view of an embodiment of a mandrel for a downhole tool, such as a plug assembly 33.

FIG. 10 shows an isometric view of an embodiment of a shoe for a downhole tool, such as a plug assembly 33.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well as the singular forms, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one having ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In describing the invention, it will be understood that a number of techniques and steps are disclosed. Each of these has individual benefit and each can also be used in conjunction with one or more, or in some cases all, of the other disclosed techniques. Accordingly, for the sake of clarity, this description will refrain from repeating every possible combination of the individual steps in an unnecessary fashion. Nevertheless, the specification and claims should be read with the understanding that such combinations are entirely within the scope of the invention and the claims.

A novel high shear strength thread form, method for use, and apparatuses for use are discussed herein. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one skilled in the art that the present invention may be practiced without these specific details.

The present disclosure is to be considered as an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated by the figures or description below.

The present invention will now be described by referencing the appended figures representing preferred embodiments. FIG. 1 and FIG. 2 depict a mandrel 10 preferably made of a readily milled material, such as a composite, with outer diameter 27A and inner diameter 24A. The mandrel 10 may be solid or contain an inner diameter 24A. Mandrel 10 has an angular thread 11 on the mandrel 10 outer surface 13. The thread form of thread 11 is formed by two opposing flank faces 14, that can form at an edge 17 at the major diameter 15 and/or minor diameter 16 of the thread 11. The edge 17 formed by the opposing flank faces 14 may be sharp or filleted with the understanding that manufacturing cutters, when analyzed at close proximity, will have some rounding on cutting tips. The flank faces 14 are governed by a major diameter 15, minor diameter 16, flank angle 18, and flank pitch 19. The tooth angle 20 formed by the intersection of two opposing flank faces 14 is shown to be an obtuse angle in the preferred embodiment. Thread 11 may be oriented about the mandrel 10 axis 21A in either the right-hand 25 or left-hand 26 directions of twist. Additionally, the profile of thread 11 may contain entry bevel 22, a thread relief (not shown), or be run-out as a minimum perfect thread 23.

FIG. 3 depicts a sleeve 28 preferably made of a readily milled material, such as a composite, with outer diameter 27B and inner diameter 24B. The sleeve 28 may be partially solid or contain a through inner diameter 24B. Sleeve 28 has an angular thread 11 on the sleeve 28 inner diameter 24B. The thread form of thread 11 is formed by two opposing flank faces 14, that can form at an edge 17 at the major diameter 15 and/or minor diameter 16 of the thread 11. The edge 17 formed by the opposing flank faces 14 may be sharp or filleted with the understanding that manufacturing cutters, when analyzed at close proximity, will have some rounding on cutting tips. The flank faces 14 are governed by a major diameter 15, minor diameter 16, flank angle 18, and pitch 19. The tooth angle 20 formed by the intersection of two opposing flank faces 14 is shown to be an obtuse angle in the preferred embodiment. Thread 11 may be oriented about the sleeve 28 axis 21B in either the right-hand 25 or left-hand 26 directions of twist. Additionally, the profile of thread 11 may contain entry bevel 22, a thread relief (not shown), or be run-out as a minimum perfect thread 23.

The mandrel 10 and sleeve 28 illustrated in FIG. 1-FIG. 3 make up the constituent components of a threaded connection 29 as depicted in FIG. 4. The mandrel 10 is inserted and threaded into the sleeve 28, with application of either right-hand or left-hand torque. The threaded connection 29 may be fully adjustable, internally shouldering, externally shouldering, or locked with the addition of screws, pins, thread locking compound, epoxy, etc. The wedging action between flank faces 14 of the mandrel 10 and sleeve 28 angular thread 11 when a force 30 is applied reduces the stress in an axial direction to discourage shear failure of the thread 11. The wedging action creates radial component forces to increase the collapse load into the mandrel 10 and the burst load into the sleeve 28, and to decrease the axial shear force component action on the shear diameter 114. The applied force 30 may act in compression or tension on the assembled components, may be the result of applied pressure over a piston area, or may be a result of torque applied to the threaded connection. The mandrel 10 and/or sleeve 28 may be solid tubulars; single or double ended collets with a plurality of fingers; subassemblies with expandable or collapsible keyed members containing matching thread 11 profiles; body lock ring split rings, barrel springs, or helical sleeve springs with matching thread 11 profiles that can ratchet in one or both axial directions through applied axial load or torque, and are prevented from moving in one or more directions. Both components of the thread 11 connection may have pins, rods, screws, keys, epoxy, thread locker, or any other aligning, diverting, or securing feature installed or applied to the thread or surrounding connection. Additionally, the thread 11 may be a tapered connection used for high shear strength and thread sealing applications utilizing lower shear strength materials, such as composites.

FIG. 5 illustrates the general threaded connection 29 utilizing angular thread 11 as shown in FIG. 4, with structural fiber layer 31 orientation detailed for each component, in the case of layered manufacturing methods such as, but not limited to, filament winding, convolute winding, sheet wrapping, sheet laminate, or any other additive form of manufacturing; and in the case of molded component manufacturing where structural fiber orientation is controlled through the use of pre-forms and mold design. FIG. 5A depicts one embodiment of the mating components of the threaded connection 29 utilizing angular thread 11 constructed from a structural fiber layer 31 orientation that is circumferentially oriented about the axis 21C of each component. FIG. 5B depicts an embodiment of the mating components of the threaded connection 29 utilizing angular thread 11 constructed from a structural fiber layer 31 orientation that is conically oriented about the axis 21C of each component. The conical structural fiber layer 31 orientation shown in FIG. 5B may be oriented at a constant angle 32 from the axis 21C, a varying angle 32 pattern through the length of the component about the axis 21C, and the mating components may share the same orientation angle 32, or be composed of two dissimilar orientation angles 32. FIG. 5C depicts an embodiment of the mating components of the thread connection 29 utilizing angular thread 11 constructed from a structural fiber layer 31 orientation that is perpendicularly oriented about the axis of each component. Components used in a threaded connection 29 utilizing angular thread 11 may be of any combination of material utilizing structural fiber layer 31 orientation commonly seen with composites, molded plastics, additive manufactured materials, and/or may be combined in any combination with components made from isotropic material properties, uniformly distributed crystalline structures, and/or disintegrating electrolytic material.

Referring to FIG. 6-8 in the preferred embodiment a fracturing plug, bridge plug, or cement retainer 33 has a first end 36 and a second end 37. Plug assembly 33 is shown as a fracturing plug, but it may be modified to become a bridge plug, cement retainer, or other plug. Fracturing plug 33 is made of a readily milled material, such as composite, ceramic, molded phenolic, low density metal, and/or similar material. Mandrel 34 may optionally have a passage 35 that can be optionally closed with a ball landed on a seat, with a valve (not shown), or with an installed plug (not shown). Mandrel 34 has pins 38 installed in an orientation to intersect the axis 39. Pins 38 may optionally be installed into mandrel 34 in an orientation that does not intersect the axis 39, through mandrel major diameter 40 and/or through inner diameter 41. Additionally, pins 38 may be installed in a circularly symmetric or circularly asymmetric pattern relative to axis 39, and pins 38 comprise of non-metallic composite materials that is easily drillable. Mandrel 34 has a plurality of spot faces 57 on outer diameter 58 of first end 36, for installation of shear screws 59 to assemble the plug assembly 33 to the wireline adapter kit 93 during run in. The shear screws 59 may be screws, pins, dog point screws, or any other form of fastener, and are comprised of brass, bronze, steel, composite, plastic, or any other material with a known shear value. A conical surface 115, joins mandrel 34 major diameter 40 and seal diameter 111, and is adjacent to the load ring 42. Mandrel 34 has a male angular thread 11 on the second end 37 to attach shoe 76 when plug assembly 33 is fully assembled. Angular thread 11 facilitates the need to withstand shear stress as a result of impact force on the shoe 67, applied setting force through the plug assembly 33 or through supplied differential from the second end 37, in cases such as, but not limited to, a bridge plug application or flow back operations. A ball diverting pin 60 is installed in the second end 37 of the mandrel, through the passage 35 and axis 39, and held in place through bonding and/or radially secured through installation of the shoe 76 to prevent a ball (not shown) from plugging passage 35 from the second end 37 of the plug assembly 33 during flow back operations. Additionally, clutch 61 is located on the first end 36 of mandrel 34, to facilitate anti rotation between multiple plug assemblies 33 during mill out operations by enabling opposed surfaces 62 and 63 to receive and rotationally lock opposed faces 89 and 90 from shoe 76 clutch 88. Mandrel 34 comprises non-metallic composite materials that are easily drillable. Mandrel 34 is the general support for each of the other components of the plug assembly 33, as described below.

Load Ring 42 inner diameter has a conically tapered surface (not shown) on which load ring 42 shoulders on mandrel 34 conical surface 115. Load ring shoulder 47 supports slip 44. Load ring 42 has a plurality of slots 43 in which slip 44 protrusions 55 are guided between opposed surfaces 45 and 46. Load Ring 42 comprises non-metallic composite materials that are easily drillable. Slip 44 has hard wickers 48 for penetrating casing wall 67 when set, for anchoring axially in place when pressure (P) is supplied. Slip 44 is made from readily milled material, such as low density metallic materials, composite, and/or molded phenolic, and hard wickers 48 may be the result of surface hardening treatments during manufacturing or the result of hard inserts (not shown) installed into slip 44, such that slip petals 52 can penetrate casing wall 67 and anchor fracturing plug 33 in place, while providing brittle hardened wickers 48 that do not hinder mill out performance. Slip 44 has a plurality of cuts 49 with opposing surfaces 50 and 51, that allow the slip 44 to break into a plurality of petals 52. Slip 44 has a plurality of protrusions 55 that are held between load ring 42 slots 43 surfaces 45 and 46, that prevent rotation of the slip and adjacent components during milling operations and ensure that petals 52 are uniformly oriented and circularly symmetric when plug assembly 33 is in the set position, shown in FIG. 8. Slip 44 inner diameter has a conically tapered surface (not shown) on which slip 44 shoulders adjacently on cone 53 conically tapered surface 54. Cone 53 has pin holes 64 that receive pins 55 installed in an orientation to intersect the axis 39, although pins 55 may optionally be installed in a circularly symmetric or circularly asymmetric pattern relative to axis 39. Pins 55 are installed into mandrel 34 until they are under mandrel 34 seal diameter 111. The pins 55 may be pins, screws, dog point screws, or any other form of fastener, and are comprised of brass, bronze, steel, composite, plastic, or any other material with a known shear value. Downhole end of cone 53 (e.g. in the direction of second end 37) has a conically tapered surface (not shown) on which cone 53 shoulders adjacently on top element 56.

Packing element 65 contains top element 56 and end element 66. Packing element 65 is disposed between cone 53 and lower cone 68. Top element 56 and end element 66 may be composed of elastomeric, graphite, and/or other polymeric material, and contain extrusion resistant features such as fibers, wire, and/or mesh. Packing element 65 is predisposed to a radially outward position 65A as force is transmitted to the top element 56, urging top element 56 to a sealing engagement with the casing wall 67 and seal diameter 111 of mandrel 34, and urging end element 66 to an expanded state to mechanically support top element 56 when pressure (P) is supplied, such as seen in FIG. 8. End element 66 of packing element 65 abuts lower cone 68.

Lower cone 68 has a conically tapered internal surface (not shown) that abuts end element 66 with a plurality of slots 69 disposed rotationally about the axis 39, through tapered surface. Slots 69 are adjacent to groove 70, which has opposite faces 72 and 73, forming backup 71. Backup 71 is predisposed to a radially outward position 71A as force is transmitted through packing element 65 to lower cone 68, urging backup 71 to expand radially outward to casing wall 67 and axially downward until face 72 of groove 70 is adjacent to face 73, and backup 71 splits into a plurality of circumferentially distributed backup petals 74 about axis 39, such as seen in FIG. 8. Lower cone 68 has pin holes 64 that receive pins 55 installed in an orientation to intersect the axis 39, although pins 55 may optionally be installed in a circularly symmetric or circularly asymmetric pattern relative to axis 39. Pins 55 are installed into mandrel 34 until they are under mandrel 34 seal diameter 111. The pins 55 may be pins, screws, dog point screws, or any other form of fastener, and are comprised of brass, bronze, steel, composite, plastic, or any other material with a known shear value. Lower cone 68 has a conically tapered surface 75 which adjacently shoulders on the conically tapered inner diameter surface (not shown) of second slip 44. A second slip 44 is disposed adjacently between lower cone 68 and shoe 76, and slip 44 has a plurality of protrusions 55 that are held between shoe 76 slots 77 surfaces 78 and 79, that prevent rotation of the slip and adjacent components during milling operations and ensure that petals 52 are uniformly oriented and circularly symmetric when plug assembly 33 is in the set position, such as FIG. 8. Second slip 44 is made from readily milled material, such as low density metallic materials, composite, and/or molded phenolic, and hard wickers 48 may be the result of surface hardening treatments during manufacturing or the result of hard inserts (not shown) installed into slip 44, such that slip petals 52 can penetrate casing wall 67 and anchor fracturing plug 33 in place, while providing brittle hardened wickers 48 that do not hinder mill out performance.

Shoe 76 has a circularly curved tapered face 80 to assist access into restrictions or any other inner diameter changes that may exist in a wellbore during run in. Clutch 88 is located on the second end 37 of shoe 76, to facilitate anti rotation between multiple plug assemblies 33 during mill out operations by enabling opposed surfaces 89 and 90 to enter and rotationally lock between opposed faces 62 and 63 from mandrel 34 clutch 61. Shoe 76 has a groove 81 on major diameter 82, as shown in FIG. 8, for use as an installation and securement point for a pump down ring 83, which enables additional run in speed with less applied surface pump flow rate during wireline run in operations. In the preferred embodiment groove 81 is defined by two opposed faces 84 and 85, between which the pump down ring 83 is installed, has two opposed undercuts to form a t-slot configuration (not shown), minor outer diameter 86, and chamfer 87. Groove 81 may optionally have any combination of opposed angular faces forming a dovetail, be constructed with or out without t-slot undercuts, may be located on curved tapered face 80, have serrations on minor outer diameter 86, or the addition of a milled cutout for installation and removal of the pump down ring 83. Shoe 76 has a female angular thread 11 on the inner diameter for the length of shoe 76, shown in FIG. 10, to attach to mandrel 34 when plug assembly 33 is fully assembled. Angular thread 11 facilitates the need to withstand shear stress as a result of impact force on the shoe 76, applied setting force through the plug assembly 33 or through supplied pressure (P) differential from the second end 37, in cases such as, but not limited to, a bridge plug application or flow back operations. Optionally, shoe 76 inner diameter may extend through the entire length of shoe 76, have a second minor inner diameter (not shown), or have a solid second end 37. Shoe 76 may have thread locker, epoxy, or other anti-rotation compound applied to thread 11 between mandrel 34 and shoe 76 for assembly purposes. Additionally pins 116, screws, dog point screws, or any other fastener comprised of easily drillable material may be installed in a circularly symmetric or circularly asymmetric pattern relative to axis 39, in an orientation that does or does not intersect the axis 39, through shoe 76 minor outer diameter 86 and/or major diameter 82 and through thread 11 of both shoe 76 and mandrel 34. Shoe 76 comprises non-metallic composite materials that are easily drillable. Pump down ring 83 can optionally be installed into or removed from grove 81, depending on operational requirements, for increased pump down speed relative to pump rate, and reduced fluid pumped to reach target setting depth during run in. Pump down ring 83 has a plurality of bypass slots 91 to allow a small amount of fluid bypass in the event that a fracturing plug bottom hole assembly must be removed from the wellbore prior to setting fracturing plug assembly 33, to avoid swabbing the formation. Pump down ring 83 may be composed of elastomeric, graphite, and/or other polymeric material, and contain extrusion resistant features such as fibers, wire, and/or mesh, and may optionally be secured into grove 81 with screws, pins, and/or epoxy.

Referring to FIG. 7, plug assembly 33 is joined to the setting tool 92 through the wireline adapter kit 93. Wireline adapter kit components are comprised of metallic materials. The adjusting nut 100 fastens directly to the setting tool 92 through a threaded connection, and is secured in place with set screws 101. Setting sleeve 99 is threaded directly to the adjusting nut 100, and has a variably thread engagement length in order to account to minimum and maximum material conditions dependent on manufacturing tolerances. Setting sleeve 99 has a plurality of shear screws 98 installed, and setting sleeve will be threaded in the second end 37 direction until shear screw 98 is adjacent to shoulder 97 during rig up, resulting in gap 103 between setting sleeve 99 and load ring 42. Following placement of shear screw 98 adjacently with shoulder 97, a plurality of set screws 102 are installed through setting sleeve 99 to secure in place against adjusting nut 100. Setting sleeve 99 additionally has entry bevel 104 to assist in entry to any casing or equipment inner diameter changes (not shown) when pulling out of hole and holes 105 to allow for fluid bypass within the wireline adapter kit 93. The tension mandrel 94 provides a direct mechanical link between setting tool 92 and plug assembly 33. The first end 36 of the tension mandrel 94 fastens directly to the setting tool 92 through a threaded connection, and is secured in place with set screws 95. The second end 37 of the tension mandrel 94 joins with the plug assembly 33 through installation of a plurality of shear screws 59 through tensions mandrel and into mandrel 34 spot faces 57. Tension mandrel has a plurality of flow bypass ports 96, for fluid bypass through the wireline adapter kit 93. Additionally, tension mandrel 94 has shoulder 97 for interaction with shear screw 98, to act as a pre-set prevention mechanism by preventing force directed into the setting sleeve 99 from prematurely transferring into and setting the plug assembly 33. The shear screws 98 may be screws, pins, dog point screws, or any other form of fastener, and are comprised of brass, bronze, steel, composite, plastic, or any other material with a known shear value. Additionally, interface between tension mandrel 94 and mandrel 34 is configured such that a ball may be optionally place within the mandrel 34 during run in without interfering with assembly of the wireline adapter kit 93 and plug assembly 33.

Referring to FIG. 6-8, a plug assembly 33 setting sequence is initiated when a signal from service is sent down hole and activates setting tool 92 (in the case of wireline conveyed applications). In the preferred embodiment shown in FIG. 7, setting tool 92 is shown as a Baker Hughes E-4 Wireline Pressure Setting Assembly Size 20 for reference in description of the setting sequence below, however plug assembly 33 and wireline adapter kit 93 may optionally be used with any other downhole setting tool. Activation of setting tool 92 transmits force (F) into adjusting nut 100 and setting sleeve 99 through the threaded connection joining these components, due to axial movement of the crosslink sleeve 106 relative to setting mandrel 107. The setting mandrel 107 may optionally be assumed to be in a fixed location during the setting event, as all component movement and interactions between setting tool 92, wireline adapter kit 93, and plug assembly 33, occur relative to location of the setting mandrel 107. A shear event occurs when a threshold value of applied force (F) is encountered by shear screws 98, which fails in shear between setting sleeve 99 and tension mandrel 94 and allows the setting tool 92, adjusting nut 100, and setting sleeve 99 subassembly to continue axial movement and close off gap 103. Once setting sleeve 99 has made contact with load ring 42 during the setting event, the applied load path through the plug assembly 33 is the following. An axially compressive load from the first end 36 to the second end 37 of plug assembly 33 is the result of the applied force (F) from setting tool 92 activation, and is applied to the load ring 42, first slip 44, cone 53, pins 55, top element 55, end element 66, lower cone 68, second slip 44, and shoe 76. An axially tensile load from second end 37 top first end 36 of plug assembly 33 is applied to the mandrel 34. Thread 11 between mandrel 34 and shoe 76 is loaded in shear over shear diameter 31, where the novel design of thread 11 form reduces stress in the axial direction to discourage shear failure of thread 11 by creating radial inward and outward component forces of the applied force (F) that load shoe 76 in a burst condition and mandrel 34 in a collapse condition. Continuing the applied load path, the shear screws 59 are loaded in shear between the tension mandrel 94 and the mandrel 34 spot faces 57.

During setting of plug assembly 33, continued applied force (F) and movement of the setting sleeve 99 creates the following setting sequence. Load ring 42 moves axially toward direction of second end 37 relative to mandrel 34. First slip 44 moves axially toward second end 37, is forced apart in slots 49 from axial and radial interaction with conical face 54 of cone 53, forming a plurality of circumferentially distributed petals 52. Petals 52 are guided radially outward through interaction between load ring 42 slots 43 and slip 44 protrusions 55 until wickers 48 broach and anchor within casing wall 67. Cone 53 transmits applied force into pins 55 until a threshold shear value is exceeded, at which point cone 53 is able to move axially toward second end 37. Applied load transmitted through cone 53 top element 56 and subsequently end element 66 to compress and expand radially outward until contact with casing wall 67 is made, bridging annular space between casing wall 67 and mandrel 34 seal diameter 111. Backup feature 71 of lower cone 68 is urged radially outward with application of force (F), forming backup petals 74. Force (F) is transmitted through backup petals face 72 to opposing face 73 and into pins 55 until a threshold shear value is exceeded, at which point lower cone 68 is able to move axially toward second end 37. Lower cone 68 moves axially toward second end 37 and into second slip 44. Second slip 44 is forced apart in slots 49 from axial and radial interaction with conical face 54 of cone 53, forming a plurality of circumferentially distributed petals 52. Petals 52 are guided radially outward through interaction between shoe 76 slots 77 and slip 44 protrusions 55 until wickers 48 broach and anchor within casing wall 67. Continue application of setting force (F) is transmitted into shear screws 59. A shear event occurs when a threshold value of applied force (F) is encountered by shear screws 59, which fails in shear between tension mandrel 94 and mandrel 34, and allows the setting tool 92, release from set plug 108 and be removed from the wellbore.

When plug assembly 33 is set, mandrel 34 and shoe 76 are free to move axially relative to load ring 42, first slip 44, cone 53, pins 55, top element 55, end element 66, lower cone 68, second slip 44. The components that mandrel 34 and shoe 76 are free to move axially relative to make up the anchoring subassembly 109. The components that move freely relative to anchoring subassembly 109, in this case mandrel 34 and shoe 76, compromise the moveable subassembly 110. Immediately following setting of plug assembly 33, the anchoring subassembly 109 is adjacent to the first end 36 side of shoe 76. When a positive pressure (P) differential is applied across the plug assembly 33 from the first end 36 to the second end 37, such as a pressure differential generated by flow through plug assembly 33 from top annulus 112 to bottom annulus 113 or a ball (not shown) landing on seat within plug assembly 33, moveable subassembly 110 moves axially downward (e.g. in the second end 37 direction) until load ring 42 of anchoring subassembly 109 is adjacent to mandrel 34 of moveable subassembly 110. Applied positive pressure (P) in this configuration generates a hoop loading condition through the second slip 44 and lower cone 68, resulting from a piston force generated by the applied pressure, which can be more than an order of magnitude greater that setting force (F) seen by plug assembly 33. Increases in positive pressure in top annulus 112 is supported by the anchoring subassembly 109 and the ball (not shown) on seat within mandrel 34, and the wellbore treatment can commence. When a positive pressure (P) differential is applied across the plug assembly 33 from the second end 37 to the first end 36, such as a pressure differential generated by flow through plug assembly 33 from bottom annulus 113 to top annulus 112 or a pressure differential applied from the bottom annulus 113 in the case of a bridge plug or other restricted mandrel 34 inner diameter (not shown) scenario, moveable subassembly 110 moves axially upward (e.g. in the first end 36 direction) until second slip 44 of anchoring subassembly 109 is adjacent to shoe 76 of moveable subassembly 110. Applied positive pressure (P) from the plug assembly 33 second end 37 in this configuration generates a hoop loading condition through the slip 44 and cone 53, resulting from a piston force generated by the applied pressure, which can be more than an order of magnitude greater that setting force (F) seen by plug assembly 33. Composite components, such as those used in this preferred embodiment, are generally significantly stronger in hoop loading conditions than they are in shear loading conditions, and stronger in singular loading rather than combined loading. The novel aligning feature formed by both load ring 42 slot 43 and slip 44 protrusions 55, and shoe 76 slots 77 and slip 44 protrusions 55, urge slip petal 52 to follow slot 43 radially outward during the setting sequence, ensuring that all petals 52 remain aligned with all slots 43. Through alignment with slots 43 in both the load ring 42 and shoe 76, the slip petals 52 formed during the setting event are evenly circumferentially positioned on both the upper cone 53 and lower cone 68, resulting in a uniformly symmetric load distribution applied to either supporting cone. Due to the reduction in asymmetric stress concentrations, cone 54 and lower cone 76 construction volume and length may be reduced, and/or lower density metallic or non-metallic materials may be employed, resulting in reduced plug assembly 33 volume required to be milled out or dissolved after a hydraulic fracturing completion.

Alternatively, plug assembly 33 may include an additional angular thread 11 connection to support shear load supplied through first end 36 of mandrel 34 through seal diameter 11, by the addition of an upper sleeve (not shown) that threads to mandrel 34 over that same shear diameter, instead of mandrel 34 being of one piece. Additionally, angular thread 11 may optionally be utilized as a body lock ring thread with a mating body lock ring (not shown) with a matching angular thread, in application that required movement from one direction and restriction of movement from the opposite direction, such as retaining pack off of a packing element and slip subassembly (not shown). Optionally, angular thread 11 may be used as a latching and/or anchoring profile for indicating apparatuses, such as, but not limited to, angular thread 11 used as a latching profile for plug setting mechanism that does not require shear screws or a location indicating profile within a wellbore when high shear forces are encountered. Lastly, angular thread 11 may optionally be used as a controlled shear profile for applications where large shear events are required without the used of metallic shear screws, pins, or other shear devices, and additionally in applications that may required the need to adjust shear values by modifying thread engagement of angular thread 11.

The teachings of the present disclosure may be used in a variety of well operations. These operations may involve using one or more treatment agents to treat a formation, the fluids resident in a formation, a wellbore, and/or equipment in the wellbore, such as production tubing. The treatment agents may be in the form of liquids, gases, solids, semisolids, and mixtures thereof. Illustrative treatment agents include, but are not limited to, fracturing fluids, acids, steam, water, brine, anti-corrosion agents, cement, permeability modifies, drilling muds, emulsifiers, tracers, flow improvers, etc. Illustrative well operations include, but are not limited to, hydraulic fracturing, stimulation, tracer injection, cleaning, acidizing, steam injection, water flooding, cementing, etc.

While preferred materials for elements of the invention (e.g. components) have been described, the apparatuses of the present invention are not limited by these materials. Wood, plastics, fiber reinforced phenolics, fiber reinforced resins, elastomers, foam, metal alloys, sintered metals, ceramics, fiber or fabric reinforce composites, and other materials may comprise some or all of the elements of the High Shear Strength Mating Helical Thread Form for Downhole Tools and apparatuses in various embodiments of the present invention.

Although the present invention has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present invention, are contemplated thereby, and are intended to be covered by the following claims.

SUMMARY OF THE INVENTION

The present invention comprises a novel high shear strength thread form generally consisting of angular geometry, such that the thread profile forms a shallow, obtuse angular shape formed by flank angles of equal but opposing angles relative to the axis of the thread that join at a major diameter (e.g. peak) and at a minor thread diameter (e.g. valley), with equal lengths of opposing flank faces, and whose angles are such that the majority of applied loads imparted onto the thread are diverted radially inward and outward rather than axially. The thread height, flank angles, and pitch may vary, and the thread may be a straight thread or tapered thread, and either of right or left-hand form. The thread form may be used for fastening, variable positioning, as a locking device about which a ratcheting male or female component may be allowed to move in one direction but impeded in the opposite direction, or as an anchoring profile for a collet, latch, or radially moveable key. In preferred embodiments, one or more of the mating components that utilize this thread form are manufactured from materials with weak shear strength material properties or anisotropic material properties, such as, but not limited to composite, magnesium alloys, and molded plastics, such as for use in fracturing plugs, bridge plugs, and/or cement retainers.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well as the singular forms, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one having ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In describing the invention, it will be understood that a number of techniques and steps are disclosed. Each of these has individual benefit and each can also be used in conjunction with one or more, or in some cases all, of the other disclosed techniques. Accordingly, for the sake of clarity, this description will refrain from repeating every possible combination of the individual steps in an unnecessary fashion. Nevertheless, the specification and claims should be read with the understanding that such combinations are entirely within the scope of the invention and the claims.

A novel high shear strength thread form, method for use, and apparatuses for use are discussed herein. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one skilled in the art that the present invention may be practiced without these specific details.

The present disclosure is to be considered as an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated by the figures or description below.

The present invention will now be described by referencing the appended figures representing preferred embodiments. FIG. 1 and FIG. 2 depict a mandrel 10 preferably made of a readily milled material, such as a composite, with outer diameter 27A and inner diameter 24A. The mandrel 10 may be solid or contain an inner diameter 24A. Mandrel 10 has an angular thread 11 on the mandrel 10 outer surface 13. The thread form of thread 11 is formed by two opposing flank faces 14, that can form at an edge 17 at the major diameter 15 and/or minor diameter 16 of the thread 11. The edge 17 formed by the opposing flank faces 14 may be sharp or filleted with the understanding that manufacturing cutters, when analyzed at close proximity, will have some rounding on cutting tips. The flank faces 14 are governed by a major diameter 15, minor diameter 16, flank angle 18, and pitch 19. The tooth angle 20 formed by the intersection of two opposing flank faces 14 is shown to be an obtuse angle in the preferred embodiment. Thread 11 may be oriented about the mandrel 10 axis 21A in either the right-hand 25 or left-hand 26 directions of twist. Additionally, the profile of thread 11 may contain entry bevel 22, a thread relief (not shown), or be run-out as a minimum perfect thread 23.

FIG. 3 depicts a sleeve 28 preferably made of a readily milled material, such as a composite, with outer diameter 27B and inner diameter 24B. The sleeve 28 may be partially solid or contain a through inner diameter 24B. Sleeve 28 has an angular thread 11 on the sleeve 28 inner diameter 24B. The thread form of thread 11 is formed by two opposing flank faces 14, that can form at an edge 17 at the major diameter 15 and/or minor diameter 16 of the thread 11. The edge 17 formed by the opposing flank faces 14 may be sharp or filleted with the understanding that manufacturing cutters, when analyzed at close proximity, will have some rounding on cutting tips. The flank faces 14 are governed by a major diameter 15, minor diameter 16, flank angle 18, and pitch 19. The tooth angle 20 formed by the intersection of two opposing flank faces 14 is shown to be an obtuse angle in the preferred embodiment. Thread 11 may be oriented about the sleeve 28 axis 21B in either the right-hand 25 or left-hand 26 directions of twist. Additionally, the profile of thread 11 may contain entry bevel 22, a thread relief (not shown), or be run-out as a minimum perfect thread 23.

The mandrel 10 and sleeve 28 illustrated in FIG. 1-FIG. 3 make up the constituent components of a threaded connection 29 as depicted in FIG. 4. The mandrel 10 is inserted and threaded into the sleeve 28, with application of either right-hand or left-hand torque. The threaded connection 29 may be fully adjustable, internally shouldering, externally shouldering, or locked with the addition of screws, pins, thread locking compound, epoxy, etc. The wedging action between flank faces 14 of the mandrel 10 and sleeve 28 angular thread 11 when a force 30 is applied reduces the stress in an axial direction to discourage shear failure of the thread 11. The wedging action creates radial component forces to increase the collapse load into the mandrel 10 and the burst load into the sleeve 28, and to decrease the axial shear force component action on the shear diameter 114. The applied force 30 may act in compression or tension on the assembled components, may be the result of applied pressure over a piston area, or may be a result of torque applied to the threaded connection. The mandrel 10 and/or sleeve 28 may be solid tubulars; single or double ended collets with a plurality of fingers; subassemblies with expandable or collapsible keyed members containing matching thread 11 profiles; body lock ring split rings, barrel springs, or helical sleeve springs with matching thread 11 profiles that can ratchet in one or both axial directions through applied axial load or torque, and are prevented from moving on one or more directions. Both components of the thread 11 connection may have pins, rods, screws, keys, epoxy, thread locker, or any other aligning, diverting, or securing feature installed or applied to the thread or surrounding connection. Additionally, the thread 11 may be a tapered connection used for high shear strength and thread sealing applications utilizing lower shear strength materials, such as composites.

FIG. 5 illustrates the general threaded connection 29 utilizing angular thread 11 as shown in FIG. 4, with structural fiber layer 31 orientation detailed for each component, in the case of layered manufacturing methods such as, but not limited to, filament winding, convolute winding, sheet wrapping, sheet laminate, or any other additive form of manufacturing; and in the case of molded component manufacturing where structural fiber orientation is controlled through the use of pre-forms and mold design. FIG. 5A depicts one embodiment of the mating components of the threaded connection 29 utilizing angular thread 11 constructed from a structural fiber layer 31 orientation that is circumferentially oriented about the axis 21C of each component. FIG. 5B depicts an embodiment of the mating components of the threaded connection 29 utilizing angular thread 11 constructed from a structural fiber layer 31 orientation that is conically oriented about the axis 21C of each component. The conical structural fiber layer 31 orientation shown in FIG. 5B may be oriented at a constant angle 32 from the axis 21C, a varying angle 32 pattern through the length of the component about the axis 21C, and the mating components may share the same orientation angle 32, or be composed of two dissimilar orientation angles 32. FIG. 5C depicts an embodiment of the mating components of the thread connection 29 utilizing angular thread 11 constructed from a structural fiber layer 31 orientation that is perpendicularly oriented about the axis of each component. Components used in a threaded connection 29 utilizing angular thread 11 may be of any combination of material utilizing structural fiber layer 31 orientation commonly seen with composites, molded plastics, additive manufactured materials, and/or may be combined in any combination with components made from isotropic material properties, uniformly distributed crystalline structures, and/or disintegrating electrolytic material.

Referring to FIG. 6-8 in the preferred embodiment a fracturing plug, bridge plug, or cement retainer 33 has a first end 36 and a second end 37. Plug assembly 33 is shown as a fracturing plug, but it may be modified to become a bridge plug, cement retainer, or other plug. Fracturing plug 33 is made of a readily milled material, such as composite, ceramic, molded phenolic, low density metal, and/or similar material. Mandrel 34 can optionally have a passage 35 that can be optionally closed with a ball landed on a seat, with a valve (not shown), or with an installed plug (not shown). Mandrel 34 has pins 38 installed in an orientation to intersect the axis 39. Pins 38 may optionally be installed into mandrel 34 in an orientation that does not intersect the axis 39, through mandrel major diameter 40 and/or through inner diameter 41. Additionally, pins 38 may be installed in a circularly symmetric or circularly asymmetric pattern relative to axis 39, and pins 38 comprise of non-metallic composite materials that is easily drillable. Mandrel 34 has a plurality of spot faces 57 on outer diameter 58 of first end 36, for installation of shear screws 59 to assemble the plug assembly 33 to the wireline adapter kit 93 during run in. The shear screws 59 may be screws, pins, dog point screws, or any other form of fastener, and are comprised of brass, bronze, steel, composite, plastic, or any other material with a known shear value. A conical surface 115, joins mandrel 34 major diameter 40 and seal diameter 111, and is adjacent to the load ring 42. Mandrel 34 has a male angular thread 11 on the second end 37 to attach shoe 76 when plug assembly 33 is fully assembled. Angular thread 11 facilitates the need to withstand shear stress as a result of impact force on the shoe 67, applied setting force through the plug assembly 33 or through supplied differential from the second end 37, in cases such as, but not limited to, a bridge plug application or flow back operations. A ball diverting pin 60 is installed in the second end 37 of the mandrel, through the passage 35 and axis 39, and held in place through bonding and/or radially secured through installation of the shoe 76 to prevent a ball (not shown) from plugging passage 35 from the second end 37 of the plug assembly 33 during flow back operations. Additionally, clutch 61 is located on the first end 36 of mandrel 34, to facilitate anti rotation between multiple plug assemblies 33 during mill out operations by enabling opposed surfaces 62 and 63 to receive and rotationally lock opposed faces 89 and 90 from shoe 76 clutch 88. Mandrel 34 comprises non-metallic composite materials that are easily drillable. Mandrel 34 is the general support for each of the other components of the plug assembly 33, as described below.

Load Ring 42 inner diameter has a conically tapered surface (not shown) on which load ring 42 shoulders on mandrel 34 conical surface 115. Load ring shoulder 47 supports slip 44. Load ring 42 has a plurality of slots 43 in which slip 44 protrusions 55 are guided between opposed surfaces 45 and 46. Load Ring 42 comprises non-metallic composite materials that are easily drillable. Slip 44 has hard wickers 48 for penetrating casing wall 67 when set, for anchoring axially in place when pressure (P) is supplied. Slip 44 is made from readily milled material, such as low density metallic materials, composite, and/or molded phenolic, and hard wickers 48 may be the result of surface hardening treatments during manufacturing or the result of hard inserts (not shown) installed into slip 44, such that slip petals 52 can penetrate casing wall 67 and anchor fracturing plug 33 in place, while providing brittle hardened wickers 48 that do not hinder mill out performance. Slip 44 has a plurality of cuts 49 with opposing surfaces 50 and 51, that allow the slip 44 to break into a plurality of petals 52. Slip 44 has a plurality of protrusions 55 that are held between load ring 42 slots 43 surfaces 45 and 46, that prevent rotation of the slip and adjacent components during milling operations and ensure that petals 52 are uniformly oriented and circularly symmetric when plug assembly 33 is in the set position, shown in FIG. 8. Slip 44 inner diameter has a conically tapered surface (not shown) on which slip 44 shoulders adjacently on cone 53 conically tapered surface 54. Cone 53 has pin holes 64 that receive pins 55 installed in an orientation to intersect the axis 39, although pins 55 may optionally be installed in a circularly symmetric or circularly asymmetric pattern relative to axis 39. Pins 55 are installed into mandrel 34 until they are under mandrel 34 seal diameter 111. The pins 55 may be pins, screws, dog point screws, or any other form of fastener, and are comprised of brass, bronze, steel, composite, plastic, or any other material with a known shear value. Downhole end of cone 53 (e.g. in the direction of second end 37) has a conically tapered surface (not shown) on which cone 53 shoulders adjacently on top element 56.

Packing element 65 contains top element 56 and end element 66. Packing element 65 is disposed between cone 53 and lower cone 68. Top element 56 and end element 66 may be composed of elastomeric, graphite, and/or other polymeric material, and contain extrusion resistant features such as fibers, wire, and/or mesh. Packing element 65 is predisposed to a radially outward position 65A as force is transmitted to the top element 56, urging top element 56 to a sealing engagement with the casing wall 67 and seal diameter 111 of mandrel 34, and urging end element 66 to an expanded state to mechanically support top element 56 when pressure (P) is supplied, such as seen in FIG. 8. End element 66 of packing element 65 abuts lower cone 68.

Lower cone 68 has a conically tapered internal surface (not shown) that abuts end element 66 with a plurality of slots 69 disposed rotationally about the axis 39, through tapered surface. Slots 69 are adjacent to groove 70, which has opposite faces 72 and 73, forming backup 71. Backup 71 is predisposed to a radially outward position 71A as force is transmitted through packing element 65 to lower cone 68, urging backup 71 to expand radially outward to casing wall 67 and axially downward until face 72 of groove 70 is adjacent to face 73, and backup 71 splits into a plurality of circumferentially distributed backup petals 74 about axis 39, such as seen in FIG. 8. Lower cone 68 has pin holes 64 that receive pins 55 installed in an orientation to intersect the axis 39, although pins 55 may optionally be installed in a circularly symmetric or circularly asymmetric pattern relative to axis 39. Pins 55 are installed into mandrel 34 until they are under mandrel 34 seal diameter 111. The pins 55 may be pins, screws, dog point screws, or any other form of fastener, and are comprised of brass, bronze, steel, composite, plastic, or any other material with a known shear value. Lower cone 68 has a conically tapered surface 75 which adjacently shoulders on the conically tapered inner diameter surface (not shown) of second slip 44. A second slip 44 is disposed adjacently between lower cone 68 and shoe 76, and slip 44 has a plurality of protrusions 55 that are held between shoe 76 slots 77 surfaces 78 and 79, that prevent rotation of the slip and adjacent components during milling operations and ensure that petals 52 are uniformly oriented and circularly symmetric when plug assembly 33 is in the set position, such as FIG. 8. Second slip 44 is made from readily milled material, such as low density metallic materials, composite, and/or molded phenolic, and hard wickers 48 may be the result of surface hardening treatments during manufacturing or the result of hard inserts (not shown) installed into slip 44, such that slip petals 52 can penetrate casing wall 67 and anchor fracturing plug 33 in place, while providing brittle hardened wickers 48 that do not hinder mill out performance.

Shoe 76 has a circularly curved tapered face 80 to assist access into restrictions or any other inner diameter changes that may exist in a wellbore during run in. Clutch 88 is located on the second end 37 of shoe 76, to facilitate anti rotation between multiple plug assemblies 33 during mill out operations by enabling opposed surfaces 89 and 90 to enter and rotationally lock between opposed faces 62 and 63 from mandrel 34 clutch 61. Shoe 76 has a groove 81 on major diameter 82, as shown in FIG. 8, for use as an installation and securement point for a pump down ring 83, which enables additional run in speed with less applied surface pump flow rate during wireline run in operations. In the preferred embodiment groove 81 is defined by two opposed faces 84 and 85, between which the pump down ring 83 is installed, has two opposed undercuts to form a t-slot configuration (not shown), minor outer diameter 86, and chamfer 87. Groove 81 may optionally have any combination of opposed angular faces forming a dovetail, be constructed with or out without t-slot undercuts, may be located on curved tapered face 80, have serrations on minor outer diameter 86, or the addition of a milled cutout for installation and removal of the pump down ring 83. Shoe 76 has a female angular thread 11 on the inner diameter for the length of shoe 76, shown in FIG. 10, to attach to mandrel 34 when plug assembly 33 is fully assembled. Angular thread 11 facilitates the need to withstand shear stress as a result of impact force on the shoe 76, applied setting force through the plug assembly 33 or through supplied pressure (P) differential from the second end 37, in cases such as, but not limited to, a bridge plug application or flow back operations. Optionally, shoe 76 inner diameter may extend through the entire length of shoe 76, have a second minor inner diameter (not shown), or have a solid second end 37. Shoe 76 may have thread locker, epoxy, or other anti-rotation compound applied to thread 11 between mandrel 34 and shoe 76 for assembly purposes. Additionally pins 116, screws, dog point screws, or any other fastener comprised of easily drillable material may be installed in a circularly symmetric or circularly asymmetric pattern relative to axis 39, in an orientation that does or does not intersect the axis 39, through shoe 76 minor outer diameter 86 and/or major diameter 82 and through thread 11 of both shoe 76 and mandrel 34. Shoe 76 comprises non-metallic composite materials that are easily drillable. Pump down ring 83 can optionally be installed into or removed from grove 81, depending on operational requirements, for increased pump down speed relative to pump rate, and reduced fluid pumped to reach target setting depth during run in. Pump down ring 83 has a plurality of bypass slots 91 to allow a small amount of fluid bypass in the event that a fracturing plug bottom hole assembly must be removed from the wellbore prior to setting fracturing plug assembly 33, to avoid swabbing the formation. Pump down ring 83 may be composed of elastomeric, graphite, and/or other polymeric material, and contain extrusion resistant features such as fibers, wire, and/or mesh, and may optionally be secured into grove 81 with screws, pins, and/or epoxy.

Referring to FIG. 7, plug assembly 33 is joined to the setting tool 92 through the wireline adapter kit 93. Wireline adapter kit components are comprised of metallic materials. The adjusting nut 100 fastens directly to the setting tool 92 through a threaded connection, and is secured in place with set screws 101. Setting sleeve 99 is threaded directly to the adjusting nut 100, and has a variably thread engagement length in order to account to minimum and maximum material conditions dependent on manufacturing tolerances. Setting sleeve 99 has a plurality of shear screws 98 installed, and setting sleeve will be threaded in the second end 37 direction until shear screw 98 is adjacent to shoulder 97 during rig up, resulting in gap 103 between setting sleeve 99 and load ring 42. Following placement of shear screw 98 adjacently with shoulder 97, a plurality of set screws 102 are installed through setting sleeve 99 to secure in place against adjusting nut 100. Setting sleeve 99 additionally has entry bevel 104 to assist in entry to any casing or equipment inner diameter changes (not shown) when pulling out of hole and holes 105 to allow for fluid bypass within the wireline adapter kit 93. The tension mandrel 94 provides a direct mechanical link between setting tool 92 and plug assembly 33. The first end 36 of the tension mandrel 94 fastens directly to the setting tool 92 through a threaded connection and is secured in place with set screws 95. The second end 37 of the tension mandrel 94 joins with the plug assembly 33 through installation of a plurality of shear screws 59 through tensions mandrel and into mandrel 34 spot faces 57. Tension mandrel has a plurality of flow bypass ports 96, for fluid bypass through the wireline adapter kit 93. Additionally, tension mandrel 94 has shoulder 97 for interaction with shear screw 98, to act as a pre-set prevention mechanism by preventing force directed into the setting sleeve 99 from prematurely transferring into and setting the plug assembly 33. The shear screws 98 may be screws, pins, dog point screws, or any other form of fastener, and are comprised of brass, bronze, steel, composite, plastic, or any other material with a known shear value. Additionally, interface between tension mandrel 94 and mandrel 34 is configured such that a ball may be optionally place within the mandrel 34 during run in without interfering with assembly of the wireline adapter kit 93 and plug assembly 33.

Referring to FIG. 6-8, a plug assembly 33 setting sequence is initiated when a signal from service is sent down hole and activates setting tool 92 (in the case of wireline conveyed applications). In the preferred embodiment shown in FIG. 7, setting tool 92 is shown as a Baker Hughes E-4 Wireline Pressure Setting Assembly Size 20 for reference in description of the setting sequence below, however plug assembly 33 and wireline adapter kit 93 may optionally be used with any other downhole setting tool. Activation of setting tool 92 transmits force (F) into adjusting nut 100 and setting sleeve 99 through the threaded connection joining these components, due to axial movement of the crosslink sleeve 106 relative to setting mandrel 107. The setting mandrel 107 may optionally be assumed to be in a fixed location during the setting event, as all component movement and interactions between setting tool 92, wireline adapter kit 93, and plug assembly 33, occur relative to location of the setting mandrel 107. A shear event occurs when a threshold value of applied force (F) is encountered by shear screws 98, which fails in shear between setting sleeve 99 and tension mandrel 94 and allows the setting tool 92, adjusting nut 100, and setting sleeve 99 subassembly to continue axial movement and close off gap 103. Once setting sleeve 99 has made contact with load ring 42 during the setting event, the applied load path through the plug assembly 33 is the following. An axially compressive load from the first end 36 to the second end 37 of plug assembly 33 is the result of the applied force (F) from setting tool 92 activation, and is applied to the load ring 42, first slip 44, cone 53, pins 55, top element 55, end element 66, lower cone 68, second slip 44, and shoe 76. An axially tensile load from second end 37 top first end 36 of plug assembly 33 is applied to the mandrel 34. Thread 11 between mandrel 34 and shoe 76 is loaded in shear over shear diameter 31, where the novel design of thread 11 form reduces stress in the axial direction to discourage shear failure of thread 11 by creating radial inward and outward component forces of the applied force (F) that load shoe 76 in a burst condition and mandrel 34 in a collapse condition. Continuing the applied load path, the shear screws 59 are loaded in shear between the tension mandrel 94 and the mandrel 34 spot faces 57.

During setting of plug assembly 33, continued applied force (F) and movement of the setting sleeve 99 creates the following setting sequence. Load ring 42 moves axially toward direction of second end 37 relative to mandrel 34. First slip 44 moves axially toward second end 37, is forced apart in slots 49 from axial and radial interaction with conical face 54 of cone 53, forming a plurality of circumferentially distributed petals 52. Petals 52 are guided radially outward through interaction between load ring 42 slots 43 and slip 44 protrusions 55 until wickers 48 broach and anchor within casing wall 67. Cone 53 transmits applied force into pins 55 until a threshold shear value is exceeded, at which point cone 53 is able to move axially toward second end 37. Applied load transmitted through cone 53 top element 56 and subsequently end element 66 to compress and expand radially outward until contact with casing wall 67 is made, bridging annular space between casing wall 67 and mandrel 34 seal diameter 111. Backup feature 71 of lower cone 68 is urged radially outward with application of force (F), forming backup petals 74. Force (F) is transmitted through backup petals face 72 to opposing face 73 and into pins 55 until a threshold shear value is exceeded, at which point lower cone 68 is able to move axially toward second end 37. Lower cone 68 moves axially toward second end 37 and into second slip 44. Second slip 44 is forced apart in slots 49 from axial and radial interaction with conical face 54 of cone 53, forming a plurality of circumferentially distributed petals 52. Petals 52 are guided radially outward through interaction between shoe 76 slots 77 and slip 44 protrusions 55 until wickers 48 broach and anchor within casing wall 67. Continue application of setting force (F) is transmitted into shear screws 59. A shear event occurs when a threshold value of applied force (F) is encountered by shear screws 59, which fails in shear between tension mandrel 94 and mandrel 34, and allows the setting tool 92, release from set plug 108 and be removed from the wellbore.

When plug assembly 33 is set, mandrel 34 and shoe 76 are free to move axially relative to load ring 42, first slip 44, cone 53, pins 55, top element 55, end element 66, lower cone 68, second slip 44. The components that mandrel 34 and shoe 76 are free to move axially relative to make up the anchoring subassembly 109. The components that move freely relative to anchoring subassembly 109, in this case mandrel 34 and shoe 76, compromise the moveable subassembly 110. Immediately following setting of plug assembly 33, the anchoring subassembly 109 is adjacent to the first end 36 side of shoe 76. When a positive pressure (P) differential is applied across the plug assembly 33 from the first end 36 to the second end 37, such as a pressure differential generated by flow through plug assembly 33 from top annulus 112 to bottom annulus 113 or a ball (not shown) landing on seat within plug assembly 33, moveable subassembly 110 moves axially downward (e.g. in the second end 37 direction) until load ring 42 of anchoring subassembly 109 is adjacent to mandrel 34 of moveable subassembly 110. Applied positive pressure (P) in this configuration generates a shear loading condition through the first end 36 of mandrel 34, through seal diameter 111, which can be more than an order of magnitude greater that setting force (F) seen by plug assembly 33. Increases in positive pressure in top annulus 112 is supported by the anchoring subassembly 109 and the ball (not shown) on seat within mandrel 34, and the wellbore treatment can commence. When a positive pressure (P) differential is applied across the plug assembly 33 from the second end 37 to the first end 36, such as a pressure differential generated by flow through plug assembly 33 from bottom annulus 113 to top annulus 112 or a pressure differential applied from the bottom annulus 113 in the case of a bridge plug or other restricted mandrel 34 inner diameter (not shown) scenario, moveable subassembly 110 moves axially upward (e.g. in the first end 36 direction) until second slip 44 of anchoring subassembly 109 is adjacent to shoe 76 of moveable subassembly 110. Applied positive pressure (P) in this configuration generates a shear loading condition through the thread 11 between mandrel 34 and shoe 76, which can be more than an order of magnitude greater that setting force (F) seen by plug assembly 33. Composite components, such as those used in this preferred embodiment, are generally significantly stronger in hoop loading conditions than they are in shear loading conditions. The novel thread 11 design withstands applied shear load from events such as, but not limited to, the setting event or pressure differentials, due to the transfer of axially directed shear load into radially distributed hoop loading to mandrel 34 and shoe 76. Due to the increase shear performance of the angular thread 11, thread engagement length may be reduced, and therefore component length may be reduced, resulting in reduced plug 33 volume required to be milled out or dissolved after a hydraulic fracturing completion.

Alternatively, plug assembly 33 may include an additional angular thread 11 connection to support shear load supplied through first end 36 of mandrel 34 through seal diameter 11, by the addition of an upper sleeve (not shown) that threads to mandrel 34 over that same shear diameter, instead of mandrel 34 being of one piece. Additionally, angular thread 11 may optionally be utilized as a body lock ring thread with a mating body lock ring (not shown) with a matching angular thread, in application that required movement from one direction and restriction of movement from the opposite direction, such as retaining pack off of a packing element and slip subassembly (not shown). Optionally, angular thread 11 may be used as a latching and/or anchoring profile for indicating apparatuses, such as, but not limited to, angular thread 11 used as a latching profile for plug setting mechanism that does not require shear screws or a location indicating profile within a wellbore when high shear forces are encountered. Lastly, angular thread 11 may optionally be used as a controlled shear profile for applications where large shear events are required without the used of metallic shear screws, pins, or other shear devices, and additionally in applications that may required the need to adjust shear values by modifying thread engagement of angular thread 11.

The teachings of the present disclosure may be used in a variety of well operations. These operations may involve using one or more treatment agents to treat a formation, the fluids resident in a formation, a wellbore, and/or equipment in the wellbore, such as production tubing. The treatment agents may be in the form of liquids, gases, solids, semisolids, and mixtures thereof. Illustrative treatment agents include, but are not limited to, fracturing fluids, acids, steam, water, brine, anti-corrosion agents, cement, permeability modifies, drilling muds, emulsifiers, tracers, flow improvers, etc. Illustrative well operations include, but are not limited to, hydraulic fracturing, stimulation, tracer injection, cleaning, acidizing, steam injection, water flooding, cementing, etc.

While preferred materials for elements of the invention (e.g. components) have been described, the apparatuses of the present invention are not limited by these materials. Wood, plastics, fiber reinforced phenolics, fiber reinforced resins, elastomers, foam, metal alloys, sintered metals, ceramics, fiber or fabric reinforce composites, and other materials may comprise some or all of the elements of the High Shear Strength Mating Helical Thread Form for Downhole Tools and apparatuses in various embodiments of the present invention.

Although the present invention has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present invention, are contemplated thereby, and are intended to be covered by the following claims. 

What is claimed is:
 1. 2. A high shear strength accepting thread form comprising: a mandrel having a radial circumference, a first end and a second end; said mandrel exhibiting a hollow or solid inner diameter and an angler thread disposed about said radial circumference, exteriorly, composed of two opposing flank faces; said flank faces composed of a major diameter, a minor diameter, a flank angle and a flank pitch; a flank intersection forming a flank tooth angle at the connection of two flank faces exteriorly where joining flank faces create an obtuse profile angle; a sleeve composed of accepting interior angular thread for receipt of inserted mandrel; said sleeve exhibiting said accepting interior angular thread exhibiting a reciprocal angle in relation to said angular thread disposed about said radial circumference, exteriorly, composed of two opposing flank faces.
 3. The high shear strength accepting thread form of claim 2, wherein the wedging action between said accepting interior angular thread, exhibiting a reciprocal angle in relation to said exterior angular thread disposed about said radial circumference of said outer thread of the mandrel which creates a supportive communication between each opposing flank face creating radial component forces to increase the collapse load into the mandrel, decreases the burst load into the sleeve and reduce the axial shear force component action on the shear diameter.
 4. The high shear strength accepting thread form of claim 2, wherein the thread form may be oriented in a right-handed or left-handed direction of twist.
 5. The high shear strength accepting tread form of claim 2, wherein the applied force realized by the thread form lessens compression or tension forces on assembled components, dissipates the result of applied pressure over a piston area, and reduces torque applied to the threaded connection.
 6. The high shear strength accepting tread form of claim 2, wherein the mandrel and sleeve configuration may be solid tubulars, single or double ended collets with a plurality of fingers, subassemblies with expandable or collapsible keyed members containing matching thread profiles, body lock ring split rings, barrel springs, or helical sleeve springs with matching thread profiles that can ratchet in one or both axial directions through applied axial load or torque and are prevented from moving in one or more directions.
 7. The high shear strength accepting tread form of claim 2, wherein the connection between said mandrel and said sleeve may be further connected through pins, rods, screws, keys, epoxy, thread locker, or any other aligning, diverting, or securing feature installed or applied to the thread or surrounding connection.
 8. The high shear strength accepting tread form of claim 2, wherein the connection between said mandrel and said sleeve may be tapered for high shear strength and thread sealing applications utilizing lower shear strength materials, such as composites.
 9. The high shear strength accepting tread form of claim 2, wherein said thread form is constructed of structural fiber layer orientation for each component where layered manufacturing methods include filament winding, convolute winding, sheet wrapping, sheet laminate, or any other additive form of manufacturing including molded component manufacturing which may be circumferentially oriented about the axis of each component, conically oriented about the axis of each component at constant or varying angle patterns or where each component shares the same orientation angle or dissimilar orientation angles.
 10. The high shear strength accepting tread form of claim 2, wherein said thread form is constructed of structural fiber layer orientation that is perpendicularly oriented about the axis of each component.
 11. The high shear strength accepting tread form of claim 2, wherein said thread form is perpendicularly oriented about the axis of each component that may be of molded plastics, additive manufactured materials, and/or may be combined in any combination with components made from isotropic material properties, uniformly distributed crystalline structures, and/or disintegrating electrolytic material.
 12. A downhole apparatus for borehole use, comprising: a mandrel having a first and a second end; a tubular member comprising at least one external surface formed therein; a sealing element disposed on said mandrel between the first and second ends and compressible to engage a borehole; at least one slip disposed about first and/or second end of sealing element and disposed on said mandrel; said slip having a first end evidencing a tapered internal surface and a second end having one or more aligning features; a member disposed adjacent to the second end of one or more slips having at least one aligning feature such that said slip is aligned by said member aligning feature with or without the addition of further aligning components between the slip and member interface;
 13. The downhole apparatus of claim 12, wherein the components of said apparatus may be made of readily milled material, such as composite, ceramic, molded phenolic, low density metal, and/or similar material.
 14. The downhole apparatus of claim 12, wherein the mandrel may encompass a passage way that can harbor a ball landed on a seat with a valve or installed pub.
 15. The downhole apparatus of claim 12, wherein the mandrel has a plurality of spot faces for installation of shear screws.
 16. A method of slip alignment for the placement and securing of a downhole apparatus disposing said apparatus between a cone and guide member comprising the following steps: conforming said cone and said slip adjacent along tapered faces and the slip and load member shoulder adjacently against either a tapered or perpendicular face; assuring the interface between the slip and guide member shoulder is shared by a plurality of aligning features extending radially outward to control orientation of the slip relative to the load member throughout all functions of the downhole apparatus thus controlling orientation of the slip relative to the cone throughout the same functions of the downhole apparatus; confirming that the orientation of the slip and guide member is such that, when the slips ride up the cone and anchor against the wellbore wall, the resulting uniform placement of split petals impart a circumferentially symmetric load distribution into the supporting cone; confirming an alignment feature disposed between the slip and guide member interface may be features of each constituent component in the form of grooved and or guiding geometry, may be added components used to follow guide geometry, and/or a combination thereof
 17. The method of claim 16, wherein said downhole apparatus is a hydraulic fracturing plugs, bridge plugs, or cement retainers, consist of a mandrel with or without a through inner diameter bore, where outer components disposed concentrically about the mandrel and outer components may contain any number of load rings, slips, cones, packing elements, end stops, pins, and shearing devices.
 18. The method of claim 16, wherein a setting tool adapter kit is utilized to fasten a downhole apparatus to a setting tool and hold said downhole apparatus axially and concentrically in place
 19. The method of claim 16, wherein one or more of the components used in the slip alignment feature are manufactured to be easily milled and from materials with weak material or anisotropic material properties, such as, but not limited to composite, ceramic, molded phenolic, magnesium alloys, low density metals and molded plastics, such as for use in fracturing plugs, bridge plugs, and/or cement retainers. 